This invention relates to a process for producing L-leucine by bacterial fermentation. More particularly, it relates to a process for producing L-leucine by fermentation with mutant microorganisms of the genus Brevibacterium or Corynebacterium.
L-leucine is one of the essential amino acids. It has been used as an additive to human and animal diets and as a raw material for pharmaceutical products.
It has been reported heretofore that L-leucine can be obtained by using a microorganism which requires an amino acid such as isoleucine and methionine for its full growth (U.S. Pat. No. 3,668,073) and a mutant which is resistant to 2-thiazolealanine (British Pat. No. 1,335,210). However, the L-leucine producing ability of these known strains is generally considered to be insufficient for commercial production.